The present application relates to vehicle doors and more particularly the present application relates to a drum assembly for a power sliding door mechanism.
A typical vehicle is manufactured with a plurality of openable doors. Each door is typically mounted on hinges within a door opening. Some larger vehicles have sliding doors that slide from an open position to a closed position thus, egress and ingress of the vehicle is possible without requiring a large open area beside the vehicle to allow for pivoting of the door. This is particularly useful in parking lots where the area between the vehicles is typically not large enough to allow for full pivoting of the opening doors. Moreover, such sliding doors also allow the vehicles to have larger door openings.
Accordingly, sliding doors provide access to large door openings without requiring a large area adjacent to the vehicle, which would be required for a door that pivots on its hinge. In one configuration, a power sliding door is supported and guided by an upper track, a center track and a lower track. An upper roller is attached to the power sliding door and travels in the upper track. A lower roller is attached to a lower portion of the sliding door and runs or travels in the lower track. A hinge and roller assembly is pivotally attached to a rear portion (e.g., towards the rear of the vehicle) of the door between the upper and lower portions of the door. The hinge and roller assembly is also received in the track to allow for sliding or movement of the door.
In addition, some vehicles are equipped with sliding doors on opposite sides of a vehicle.
In addition to the usage of sliding doors in vehicles, power drive systems have been implemented wherein automatic opening, closing, locking and unlocking of the sliding door is facilitated through a drive system coupled to the sliding door. Presently, some sliding doors are driven through cables attached to the forward and aft sides of the center roller hinge (e.g., a hinge mounted towards the center of the door with respect to the upper and lower edges of the same).
Drum assemblies are used to wrap up and release a portion of the cable as the sliding door is opened and closed. The drum assemblies have a front drum and a rear drum each mounted coaxially with each other. During closing of the sliding door with the driving assembly there is an increase force at the end of the door closing using the front drum with a variable moment arm (cam) feature configured to wrap up a portion of the cable. This causes excessive cable slack unless it is not compensated for by the rear drum. In order to compensate for this excessive slack, the rear drum has a variable radius (cam) feature that is similar to the front drum.
In order to provide power drive assemblies for a vehicle having both a left hand vehicle sliding door and a right hand vehicle sliding door a pair of systems will require a total of four different drums and assembly tools (e.g., a front drum and a rear drum for both the left hand and right hand power drive assemblies). Also, and since the drums are very similar in shape and size they could easily be mixed during assembly.
Accordingly, it is desirable to provide a pair of drums for use as either a right hand side or left hand side drum assembly. Moreover, it is also desirable to provide a method for using and assembling the drums for either a left hand or right hand drum assembly of a power drive system.